code: def test_default_device(device_instance1):
      device = device_instance1
      chainerx.set_default_device(device)
      assert chainerx.get_default_device() is device
  
file_path: chainer/tests/chainerx_tests/unit_tests/test_device.py
imports: import copy
  import pickle
  import pytest
  import chainerx
label_desc: Use image node_id 8 for calling a global function with example usage: test_default_device(device_instance1) without return types